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carbs and tfi never mix!!!


Lil-Pony

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right now it sounds like i have a faulty tfi module on my bronco, it stalls and wont start after its really warmed up, this is the third one in 3 years. i would like to know what is the best route to rid this system. ive seen the 4bbrl carb on the 2.8 tech page and ive seen the durapark conversion along with something to do with an msd box.

will a the 4bbrl carb get rid of the tfi, and has anyone done it? any increase in power and torque.

if the 4bbrl doesnt work i was thinking a accel tfi or durapark conversion and a holley 350cfm 2bbrl. any advice is appreciated. also ive been thought hell looking for aftermarket headers for this damn engine.
 


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Twister

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Duraspark it and dont look back. I think alot will say to skip the holley 350 as it is too much carb for the little motor.
 

wildbill23c

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You need a bigger engine if you want a 4 barrel carb. You will have absolutely no fuel economy, and will never get it to run right because it would be pushing too much air and fuel into the engine.
 

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Well what about the holley 2bbrl
 

enginepaul

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I would check to see what's happening with your TFI. I've had two fail in over 100,000 miles. Very annoying, so I carry a spare.
Maybe excess heat or a wiring problem.
On the power side of things, you will need a bigger engine. Check the price of a manifold, carb, duraSpark and compare that to a 5.0 swap.
 

wildbill23c

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I know there was a write up somewhere on TRS about a remote TFI install which just reloacated the TFI somewhere under the dash inside the cab if I remember correctly. That's definitely something to look into.

As far as the carb, I wouldn't waste money on a 4 barrel carb for a V6, the engine can't take that much air/fuel it would be a complete waste. The 2 barrel would probably work fine, not sure how much cfm the stock motorcraft carb pulls but you would have to stay pretty close to that stock cfm number in order to get it to run correctly I believe, then again I'm not a vehicle expert, but I do know that putting too large of a carburetor on an engine will cause it to run like crap.
 

Lil-Pony

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The 2 barrel would probably work fine, not sure how much cfm the stock motorcraft carb pulls but you would have to stay pretty close to that stock cfm number in order to get it to run correctly I believe, then again I'm not a vehicle expert, but I do know that putting too large of a carburetor on an engine will cause it to run like crap.
thats what i intend on doing along with an alternator upgrade. just wanted to know what yall think before i proceed. one last question to anyone who has done this swap. manual or electric choke, and if electric, does it just get wired in place of the original choke?

stock cfm is like 290-285cfm
 

Lil-Pony

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I would check to see what's happening with your TFI. I've had two fail in over 100,000 miles. Very annoying, so I carry a spare.
Maybe excess heat or a wiring problem.
On the power side of things, you will need a bigger engine. Check the price of a manifold, carb, duraSpark and compare that to a 5.0 swap.
about 600$ for all parts new. i just want to get her running reliably. later on im droping a 342 stroker in her.
 

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If you are saying a little over $600 for the 4bbl stuff new you might want to recheck your numbers. The intake manifold for that runs around 600 by itself. The 390 cfm vacuum carb is another $300+. My 84 ran best when it had the 390 CFM double pumper, the vacuum secondary never worked quite right. The mechanical secondary version over $700. Then you still need the duraspark stuff to make it work. With this setup you probably want to figure closer to $1500 to get it with all new parts.

I know people say that the 2.8L can't handle the 390, but my experience says otherwise. Back when we had the mechanical secondary on my 84 that thing would work that carb. That motor had nothing but that intake setup, duraspark, very mild porting on the heads, long tube headers and dual exhaust. Switched to the vacuum secondary and it wouldn't run near as well, not sure if the vacuum for the secondaries wasn't there or if it never got tuned in right. Rebuilt the motor with a cam and was going to have the old mechanical carb professionally rebuilt, but I totaled the truck before I got 5000 miles on the new motor. Still have everything sitting in the truck out back, planning to build something else around that motor someday. Currently thinking about building a dune buggy type vehicle around it.

A 350 and duraspark will have you running good if you know how to tune it and you won't even need a new intake manifold.
 
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Lil-Pony

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If you are saying a little over $600 for the 4bbl stuff new you might want to recheck your numbers. The intake manifold for that runs around 600 by itself. The 390 cfm vacuum carb is another $300+. My 84 ran best when it had the 390 CFM double pumper, the vacuum secondary never worked quite right. The mechanical secondary version over $700. Then you still need the duraspark stuff to make it work. With this setup you probably want to figure closer to $1500 to get it with all new parts.

I know people say that the 2.8L can't handle the 390, but my experience says otherwise. Back when we had the mechanical secondary on my 84 that thing would work that carb. That motor had nothing but that intake setup, duraspark, very mild porting on the heads, long tube headers and dual exhaust. Switched to the vacuum secondary and it wouldn't run near as well, not sure if the vacuum for the secondaries wasn't there or if it never got tuned in right. Rebuilt the motor with a cam and was going to have the old mechanical carb professionally rebuilt, but I totaled the truck before I got 5000 miles on the new motor. Still have everything sitting in the truck out back, planning to build something else around that motor someday. Currently thinking about building a dune buggy type vehicle around it.

A 350 and duraspark will have you running good if you know how to tune it and you won't even need a new intake manifold.
srry should have gone in to more detail in previous post. thats what i meant, 600 for the complete new holley 2bbrl and duraspark conversion. bout you did notice a better feel in the 4bbrl so im guess i should feel the about the same with the 2bbrl.
 

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I imagine so, never drove the truck with a 2bbl. Dad did most of that work to the engine back in the late 80s, I was less than 5 at the time. I'm guessing that it was one of the earliest conversions to the Offy and 4bbl done on a Ranger. The truck was a former fleet truck that dad got cheap, and the carb/computer mess started acting up. Dad was a lot more familiar with the carb and duraspark (he previously had a 2.8L Pinto) so that's what he did.

You say that you are planning an engine swap in the future? If that's the case I don't think I would bother with buying all new stuff. Buy a new distributor because I think you'd be hard pressed to find one in a yard these days. Get a used Holley 350, they are easy and inexpensive to rebuild and can probably be bought for cheap. You could also do the mod to the stock carb and keep using that. There are write ups on it around but I've never done it myself. The duraspark wiring and module can be had cheap at a junkyard if you can find it. There's not much to go wrong with the wiring. The modules can be had for cheap as well, buy two and keep the second as a spare under the seat. Even buying new ones I kept one under the seat as a spare, they are easy to swap on the side of the road.
 

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I did the relocation of the TFI module....it is now mounted on the passenger side fender well. I also suggest in using the original motorcraft brand as well. Second choice would be the ACdelco brand and nothing else.

I also agree that the EEC-IV and carburetor don't mix very well. I was having much problems on my 1983.....almost went ahead and did duraspark. However, last year.....I went through all the wiring plus many of the emissions components. I rewired much plus installed many new connectors as well. It also received a new carburetor as well....it even still had the tamper proof caps over the idle mixture screws. Any ways, it now runs like it was brandnew.

It runs good.....now in the process of which gearing to go with.
 

wildbill23c

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thats what i intend on doing along with an alternator upgrade. just wanted to know what yall think before i proceed. one last question to anyone who has done this swap. manual or electric choke, and if electric, does it just get wired in place of the original choke?

stock cfm is like 290-285cfm
Personally I'd go with a manual choke. I had an 84 ford ranger, and now my 84 bronco 2, both have that electric choke garbage that doesn't work, and wastes a ton of fuel. Yank that crap out and do a manual choke, I'm planning on doing one on my bronco 2 here in the near future. Gotta lot of other to-do list things to complete first and I think my major oil leak problem is gonna take precedence over the manual choke, I got through the negative temperatures this past winter with no choke at all, so I'm not to concerned about it really.

Definitely stick with a 2 barrel carb for your truck. Your truck has an electric choke already or it should have come with one, either way it mounts on the passenger side of the carburetor. I think you have to remove the stock electric choke to do a manual choke anyhow, but mine doesn't exist anymore at all I ripped it off there as it didn't work in the first place.
 

Lil-Pony

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Personally I'd go with a manual choke. I had an 84 ford ranger, and now my 84 bronco 2, both have that electric choke garbage that doesn't work, and wastes a ton of fuel. Yank that crap out and do a manual choke, I'm planning on doing one on my bronco 2 here in the near future. Gotta lot of other to-do list things to complete first and I think my major oil leak problem is gonna take precedence over the manual choke, I got through the negative temperatures this past winter with no choke at all, so I'm not to concerned about it really.

Definitely stick with a 2 barrel carb for your truck. Your truck has an electric choke already or it should have come with one, either way it mounts on the passenger side of the carburetor. I think you have to remove the stock electric choke to do a manual choke anyhow, but mine doesn't exist anymore at all I ripped it off there as it didn't work in the first place.
Ill keep that in mind, the holley comes with a manual and they sell an add on electric ill try it out and see how well it works, and if need be il go manual if i must.
 


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